Calcium complexes for fortification of foods and process of making

ABSTRACT

A novel calcium complex for the fortification of beverages and foods, especially milk, is disclosed. The fortifying complexes contain a calcium source and a negatively-charged emulsifier with or without an organic or inorganic acid or a salt thereof. These complexes have been found to be particularly effective in fortifying milk and milk-protein containing beverages without coagulation of the proteins or without significantly changing the texture of the product.

FIELD OF INVENTION

The present invention relates to the fortification of foods andbeverages, particularly those containing milk proteins, with calcium.

BACKGROUND OF THE INVENTION

Milk is an important source of dietary calcium. Calcium, the mostabundant mineral in body, is a major constituent of bone and teeth. Thismineral also plays an important role in several physiological systems.Calcium is important for healthy bone and tooth development in the youngand therefore an adequate intake is essential. Calcium status may alsobe a factor in the development of osteoporosis in elderly people.

Since the body does not produce minerals, it is totally dependent on anexternal supply of calcium, nutritional or supplementary. The importanceof adequate calcium intake is recognized during the whole life of thehuman being. In 1994, the NIH Consensus Development Panel revisedrecommended daily allowances for calcium intake for each age group from800-1200 mg per day to 1500 mg per day.

It has been suggested that calcium in association with caseins mayimprove absorption in the gastrointestinal tract. Also it has been foundthat organic acids salts of calcium are more bioavailable in generalthan the inorganic salts. Calcium citrate has advantages over othercalcium salts for use in fortified foods because of highbioavailability. For example, calcium citrate, as opposed to calcium ingeneral, has only a marginal effect of interfering with the absorptionof other minerals, especially iron. Also, long-term calciumsupplementation with calcium citrate can reduce the risk of formation ofkidney and urinary stones since citrate ions are inhibitors forcrystallization of stone-forming calcium salts.

Addition of calcium to beverages, especially milk, can be verydifficult. If slightly or completely insoluble sources of calcium areused, precipitation of the salts can occur especially if stabilizers arenot used. If highly soluble sources of calcium (calcium chloride, etc.)are used, interation between the calcium and calcium sensitiveingredients, such as milk protein, can occur. These interactions canlead to coagulation of the ingredients during temperature treatment evenat pasteurization temperature. In addition, the pH of some calcium saltsystems may not be compatible with other ingredients or affects theflavor.

U.S. Pat. Nos. 4,701,329 and 4,851,243 disclose the use of tribasiccalcium phosphate, carrageenan, and guar in calcium- andphosphorous-enriched milk. In this system,the use of stabilizing gums isnecessary to prevent sedimentation of the insoluble calcium salt, whichalso increases the thickness of the milk.

U.S. Pat. No. 4,840,814 involves a process for preparing calciumenriched milk in which the milk is heat-treated prior to soluble calciumsalt addition. This requires additional processing, and could alsoeffect the quality of the milk. In addition, this method is limited toallowing only up to a 30 mg % increase in the calcium.

A series of patents such as U.S. Pat. Nos. 4,722,847, and 4,919,963 (andmany subsequent patents), disclose the use of calcium citrate-malatecomplexes for the fortification of beverages, beverage concentrates, andas supplements. These systems are stable when the pH is kept below pH 5.For a number of beverages this pH would result in acidic flavors andinstability of proteins, especially milk proteins. This problem is alsoencountered in U.S. Pat. Nos. 4,871,554 and 5,500,232.

EP 0709033 discloses preparation of calcium-supplemented milk drinksthrough the use of minerals extracted from whey. Although this createsproducts with good flavor and stability the level of supplementation islimited to 40 mg %.

SUMMARY OF THE INVENTION

We have developed a complex comprising a calcium source and anegatively-charged emulsifier with or without an organic or inorganicacid or a salt thereof, which may be used to fortify beverages andfoods, with improved palatability without affecting product quality.

According to the present invention, there is provided a complex formedby the interaction of a suitable calcium source, a negatively chargedemulsifier with or without an organic or inorganic acid or a saltthereof.

The complexes work particularly well in systems that containcalcium-sensitive components, such as proteins.

DETAILED DESCRIPTION OF THE INVENTION

The calcium source that is primarily used to create this complex caninclude calcium hydroxide, calcium carbonate, calcium chloride, calciumphosphate, calcium sulfate, calcium nitrate, calcium lactate, calciumfumarate, calcium citrate, calcium acetate, calcium glycerophosphate orcalcium oxide but is preferably calcium hydroxide. The use of analkaline source, such as calcium hydroxide, advantageously neutralisesthe pH of the complex. If a non-alkaline calcium source is used, then analkaline agent must be added to neutralize the pH of the complex, ofwhich any food grade alkaline agent can be utilized.

The negatively-charged emulsifiers that can be used to form the complexinclude but are not limited to citric acid esters of monoglyceridesCITREM, (Danisco Ingredients, Inc., New century, Kans.), stearoyllactylate (sodium, calcium, or acid), enzyme modified lecithin, stearylcitrate, fatty acids and their salts, or diacetyl tartaric acid estersof monoglycerides. CITREM is most preferred. The emulsifiers used arenot limited to those of a single acyl or fatty acid component, such ason a specific carbon chain length or degree of unsaturation.

The emulsifier used is preferably hydrated, making the emulsifier moredispersable, and allowing easier exchange with cations. This can beaccomplished by various means dependent on the type of emulsifier used,and are commonly known to those familiar with the art. For example, acommon method of hydration is by heating a slurry of emulsifier andwater to above 70° C. for a period of time (generally more than 10min.). Once hydrated, the emulsifier dispersion is cooled to near roomtemperature.

Any one of a number of acids can be used including organic acids such ascitric, lactic, malic, fumarate, gluconic, succinic, tartaric, orascorbic, or inorganic acids such as phosphoric. Salts of these acidsthat can be utilized include potassium, sodium, or calcium salts of theaforementioned acids. For this invention, the most preferred acid iscitric acid. Optionally, the complex may be dried and, if desired,stored before further use for fortification of a foodstuff.

The amounts needed to form the complex are not critical provided thatsufficient amounts of each component are present. Simple mixing of thecomponents is sufficient to form the complex. When an acid is not usedin the complex, the weight ratio of calcium (from the calcium source) tosurfactant should range from 1:10 to 10:1, and preferably from 2:1 to1:2. When an acid is used in the complex, the weight ratio of acid tocalcium should range from 5:1 to 1:5, and preferably from 2:1 to 1:2,while the weight ratio of calcium to surfactant can range from 100:1 to1:5. The components are preferably dissolved in water to facilitatemixing and complex formation. The concentration of the solutions arepreferably 1-5% by weight or greater. The person of ordinary skill inthe art can readily determine convenient amounts to use for anyparticular application.

The complex may conveniently be formed by the interaction of a suitablecalcium source, a negatively charged emulsifier, with or without anorganic or inorganic acid or a salt thereof. For example, the complexmay be prepared by adding acid or a salt of an acid to the emulsifierwith mixing, and then adding the calcium source.

When an alkaline calcium source such as calcium hydroxide is added, thepH of the system is neutralized. Alternately, a non-alkaline calciumsource can be added, followed by the neutralization with alkaline agent.Any food grade alkaline agent may be used for neutralisation includingbut not limited to sodium hydroxide, potassium hydroxide, magnesiumhydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate andpotassium bicarbonate.

The present invention also provides a fortified foodstuff with afortifying amount of a complex comprising calcium and anegatively-charged emulsifier with or without an organic or inorganicacid or a salt thereof.

The foodstuff may be a dairy based product such as a milk beverage, aliquid nutritional product or other beverage such as a juice, or aconfectionary product such as ice cream.

The fortified foodstuff comprising a fortifying amount of a complex maybe prepared by forming a complex and adding the complex to thefoodstuff. The foodstuff can then be heat treated by normal meanswithout any loss in quality such as precipitation, coagulation, orfouling of processing equipment. The resulting fortified foodstuff issimilar to its unfortified counterpart in organoleptic quality. It has asimilar color and taste, without major changes to the texture, viscosityor mouthfeel of the foodstuff.

The amount of complex to add to the foodstuff is not critical and isdependent upon the calcium content of the complex and the desired levelof fortification. Typically, enough of the complex would be added tofortify the foodstuff from 5% to 200% of the recommended daily allowancefor calcium, although even greater amounts are possible, if desired.

Advantageously, a stabiliser may be added to the foodstuff, preferablybefore the complex is added to the foodstuff. The stabiliser may beadded to the foodstuff in the form of an aqueous solution or suspensionor as a dry powder. Stabilisers that may be used may include but are notlimited to carrageenan, xanthan, gellan, pectin, alginates, gumarabic,carboxymethylcellulose, modified and unmodified starches,propyleneglycol alginate, locust bean gum, guar gum, hydroxylpropyl cellulose,hydroxypropylmethyl cellulose, methyl cellulose or mixtures of two ormore thereof. Preferably for dairy products, carrageenan is used as astabiliser.

The following Examples further illustrate the present invention.

EXAMPLES Example 1

The following example is intended to demonstrate that a variety ofemulsifiers and/or calcium sources can be effective in preparing thesecomplexes.

Complexes for fortification of milk were prepared according to thefollowing formulations:

    ______________________________________                                                                           Calcium                                    Sample                                                                              Emulsifier                                                                              Amount  Acid Amount                                                                              Source  Amount                             ______________________________________                                        1     SSL       2.52 g  Citric                                                                             1.19 g                                                                              Calcium 0.84 g                                                                hydroxide                                  2     CSL       5.25 g  Citric                                                                             1.58 g                                                                              Does not                                                                      apply                                      3     SSL       2.52 g  Citric                                                                             1.19 g                                                                              Calcium 3.47 g                                                                lactate                                    4     SSL       3.02 9  Citric                                                                             1.41 g                                                                              Calcium 0.84 g                                                                hydroxide                                  5     CITREM    2.97 g  Citric                                                                             1.19 g                                                                              Calcium 0.84 g                                                                hydroxide                                  6     CITREM    2.97    Citric                                                                             1.19  Calcium 0.90                                                                  hydroxide                                  ______________________________________                                         SSL = Sodium stearoyl2-lactylate, CSL = calcium stearoyl2-lactylate      

Emulsifier was mixed with 50 ml water, the dispersion was heated to 150°F., and then cooled to 100° F. For samples 1-3, a solution of the acidin 10 ml water was then added to the hydrated emulsifier with vigorousmixing. For samples 4 and 5, the acid was added directly to the hydratedemulsifier with vigorous stirring. When applicable, a dispersion of thecalcium source in 10 ml water was then added to the emulsifier-acidsuspension with vigorous stirring. 6.6 g non-fat dry milk was added to700 mL of skim milk under agitation. The resulting complex was addedwith vigorous stirring to sufficient skim milk (at 120° F.) to bring thefinal volume of calcium fortified milk to 750 mL. The pH of the milk wasadjusted to 7.0 using a 30% sodium hydroxide needed. The milk was thenhomogenized at a total pressure of 2500/500 psi using a two-stage APVRannie® Homogenizer. The fortified milk was filled into 125 ml baby foodjars, pasteurized at 163° F. for 15 sec, cooled rapidly in a ice waterbath, then stored in a refrigerator.

Samples were evaluated for sedimentation and taste after 1 week and forsedimentation after 2 weeks.

Results:

    __________________________________________________________________________    Sample                                                                            0 weeks                                                                             1 week         2 weeks                                              __________________________________________________________________________    1   no sediment                                                                         S1.sediment, s1.Emulsifier flavor                                                            some sediment                                        2   no sediment                                                                         S1.sediment, good flavor                                                                     S1.sediment                                          3   no sediment                                                                         S1.sediment, s1.Emulsifier flavor                                                            some sediment                                        4   no sediment                                                                         no sediment, good flavor                                                                     some sediment, good flavor                           5   no sediment                                                                         no sediment, good flavor                                                                     no sediment, good flavor                             6   no sediment                                                                         no sediment, good flavor                                                                     no sediment, good flavor                             __________________________________________________________________________

Example 2

i)A slurry of 450 g CITREM® was mixed with 15 kg water at roomtemperature for 60 min. The suspension was heated to 165° F. and held atthat temperature for 10 min with agitation, then cooled to 90° F.(suspension #1). A solution of 544.5 g citric acid in 6.1 kg water wasprepared by mixing at room temperature (solution #2) A sodium hydroxidesuspension was prepared by mixing 333.0 g sodium hydroxide in 5,000 gwater at room temperature (suspension #3). Solution #2 was added tosuspension #1 and mix well for 60 min. Suspension #3 was then added andthe resulting suspension was mixed for 60 min.

ii) To 10 kg skim milk at 40-60° F., 45.0 g carrageenan (SeaKem CM611,FMC Corporation, Philadelphia, Pa.) was added with mixing for 5 min. Themilk was then heated to 165° F. and held at 165° F. for 5 min underagitation.

iii) To 260 kg g skim milk, 2505.0 g non-fat dry milk (NFDM)was added at40-60° F. and the milk was mixed for 10 min. The milk was then heated to120° F., and the carrageenan/milk mixture (ii) was added slowly and theresulting milk was mixed for 5 min. The milk was heated to 149° F. andheld for 5 min. The milk was cooled to 90° F. and the calcium complexwas added slowly. The resulting calcium fortified milk was mixed for 10min and 22.5 g cream/milk flavor was added. The pH of the milk wasadjusted with 10% potassium hydroxide solution to 6.9-7.0. The solidscontent was checked.

iv)Samples were then heat treated under the following conditions.

Pateurization:

The calcium fortified milk was homogenized at 120° F. and pressure25000/500 psi. The milk was then pasteurized at 163° F. for 15 sec. andfilled into 330 mL glass bottles. The bottles of milk were then cooledin cold water and stored under refrigeration at 40° F.

UHT-pasteurization, Plate Heat Exchanger (PHE):

Calcium fortified milk was pre-heated to 160° F., then heated to 285° F.and held at 285° F. for 5 sec, and cooled to 160° F. The milk was thenhomogenized at pressure 2500/500 psi., cooled to 60° F. and filled in250 mL Tetra Brik Aseptic packages (Tetra Pak Inc., Chicago).

UHT-pasteurization Steam Injection (SI):

Calcium fortified milk was pre-heated to 175° F., then heated to 285° F.by steam injection, held at 285° F. for 5 sec, and cooled to 175° F. Themilk was homogenised at pressure 2500/500 psi, cooled to 60° F. andfilled in 250 mL Tetra Brik Aseptic packages (Tetra Pak Inc., Chicago).

UHT-sterilization (PHE):

Calcium fortified milk was pre-heated to 160° F., then heated to 298° F.by plate heat exchangers and held at 298° F. for 5 sec, and cooled to160° F. The milk was homogenised at pressure 2500/500 psi, cooled to 60°F. and filled in 250 mL Tetra Brik Aseptic packages (Tetra Pak Inc.,Chicago).

UHT-sterilization (SI):

Calcium fortified milk was pre-heated to 175° F., then heated to 298° F.by steam injection, held at 298° F. for 5 sec, and cooled to 175° F. Themilk was homogenised at pressure 2500/500 psi, cooled to 60° F. andfilled in 250 mL Tetra Brik Aseptic packages (Tetra Pak Inc., Chicago).

The results are given in the following table:

    __________________________________________________________________________    Results from Example 2                                                                           STORAGE                                                                             CENTRIFU(                                                                            CALCIUM                                                      AGE TEMP  SEDIMENT*                                                                            LEVEL**                                                                             BOILING         SENSORY                 DESCRIPTION    wk. (° F.)                                                                       (%)    (ppm) TEST***                                                                              OBSERVATIONS                                                                           EVALUATION              __________________________________________________________________________    Calcium hydroxide, citric acid,                                                              0   40    N/A    1868  No flocculation                                                                      No precipitation                                                                       Good flavor             CITREM Pasteurized                                                                           2   40    N/A    1854  No flocculation                                                                      No precipitation                                                                       Good flavor             Calcium hydroxide, citric acid,                                                              0   40    0.03   1890  No flocculation                                                                      No precipitation                                                                       Good flavor             CITREM UHT pasteurized (SI)                                                                  2   40    0.03   1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            4   40    N/A    1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            8   40    N/A    1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            8   40    N/A    1840  No flocculation                                                                      No precipitation                                                                       Good flavor             Calcium hydroxide, citric acid,                                                              0   40    N/A    1894  No flocculation                                                                      No precipitation                                                                       Good flavor             CITREM UHT pasteurized (PHE)                                                                 2   40    N/A    N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            4   40    N/A    N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            6   40    N/A    N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            8   40    N/A    1928  No flocculation                                                                      No precipitetion                                                                       Good flavor             Calcium hydroxide, citric acid,                                                              0   80    0.12   1910  No flocculation                                                                      No precipitation                                                                       Good flavor             CITREM UHT sterilized (SI)                                                                   2   80    N/A    1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            4   80    N/A    1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            6   80    N/A    1840  No flocculation                                                                      No precipitation                                                                       Good flavor                            8   80    N/A    1850  No flocculation                                                                      No precipitation                                                                       Good flavor                            11  80    0.08   N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            13  80    0.02   N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            16  80    0.04   1906  No flocculation                                                                      No precipitation,                                                                      Acceptable flavor                                                    slight getation                  Calcium hydroxide, citric acid,                                                              0   80    N/A    1910  No flocculation                                                                      No precipitation                                                                       Good flavor             CITREM UHT sterilized (PHE)                                                                  2   80    N/A    1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            4   80    N/A    1860  No flocculation                                                                      No precipitation                                                                       Good flavor                            6   80    N/A    1840  No flocculation                                                                      No precipitation                                                                       Good flavor                            8   80    N/A    1850  No flocculation                                                                      No precipitation                                                                       Good flavor                            11  80    N/A    N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            13  80    N/A    N/A   No flocculation                                                                      No precipitation                                                                       Good flavor                            16  80    N/A    1906  No flocculation                                                                      No precipitation,                                                                      Acceptable flavor                                                    slight gelation                  __________________________________________________________________________     *% sediment was determined from sediment weight after centrifugation at       1800 g for 5 min and drying of resulting pellet at room temperature           overnight                                                                     **Total calcium content was determined using a Leeman Laba, model PS 1        AESICP spectrometer after dry ashing and ash dissolving in nitric acid an     water (1:1)                                                                   ***Flocculation was determined by visual inspection. Milk was boiled 15       sec then placed immediately on the convexed surface of a watch glass for      inspection                                                               

Example 3

To 25 kg water at 185° F., 720 g CITREM were added and mixed for 5 min.,then cooled to 110° F. While under agitation 871 g citric acid wereadded, and the suspension was mixed for 5 min. 533 g calcium hydroxidewas added under agitation and the complex was mixed for 60 min. Stepsii, iii and iv from Example 2 were then followed.

The results are given in the following Table:

    __________________________________________________________________________                    Centrifuge                                                                         Calcium                                                         Age                                                                              Storage                                                                             Sediment*                                                                          Level**                                                                           Boiling    Sensory                                   Description                                                                          wk Temp (°F.)                                                                   (%)  ppm Test***                                                                            Observations                                                                        Evaluation                                __________________________________________________________________________    Calcium                                                                              0  40    0.07 2041                                                                              No flocc                                                                           No precipi-                                                                         Good                                      hydroxide,                                                                    ulation                                                                              tation                                                                           Flavor                                                              citric acid,                                                                         2  40    0.04 N/A No flocc                                                                           No precipi-                                                                         Good                                      CITREM, UHT                                                                   ulation                                                                              tation                                                                           Flavor                                                              pasteurized                                                                          4  40    0.04 N/A No flocc                                                                           No precipi-                                                                         Good                                      (SI)                                                                          ulation                                                                              tation                                                                           Flavor                                                                     6  40    0.04 N/A No flocc                                                                           No precipi-                                                                         Good                                      ulation                                                                              tation                                                                           Flavor                                                                     8  40    0.02 2048                                                                              No flocc                                                                           No precipi-                                                                         Good                                      ulation                                                                              tation                                                                           Flavor                                                                     10 40    0.04 N/A No flocc                                                                           No precipi-                                                                         Good                                      ulation                                                                              tation                                                                           Flavor                                                              __________________________________________________________________________     * % sediment was determined from sediment weight after centrifugation at      1800 × g for 5 min and drying of resulting pellet at room               temperature overnight                                                         ** Total calcium content was determined using a Leeman Labs model PS 1        AESICP spectrometer after dry ashing and ash dissolving in nitric acid an     water (1:1)                                                                   *** Flocculation was determined by visual inspection. Milk was boiled 15      sec then placed immediately on the convexed surface of a watch glass for      inspection.                                                              

Other samples from Example 3 performed very similarly to samples withcorresponding heat treatments from Example 2.

Example 4

This Example shows how the complex can be formed directly in milk.

Step 1 from Example 2 was followed to prepare a calcium complex. To 275kg milk at 40-60° F., 45.0 g SeaKem CM 611 carrageenan was added withmixing. To the milk was added 2505.0 g NFDM, 22.5 g cream/milk flavor,the Ca-complex and the resulting fortified milk was mixed for 5 min. ThepH was adjusted with 10% potassium hydroxide solution to 6.9-7.0. Thesolids content was checked. Step iv from example No 2 was then followed.

Samples from Example 4 performed very similarly to samples withcorresponding heat treatments from Example 2.

Example 5

To 800 g water at 185° F., 24.0 g CITREM was added and mixed for 5 min,then cooled to <110° F. While under agitation, 29.0 g citric acid wasadded and mixed for 5 min. Calcium hydroxide (17.77 g) was added underagitation and resulting complex was mixed for 60 min.

To 300 g skim milk at 40-60° F., 1.5 g SeaKem CM 611 carrageenan wasadded and the milk mixed for 5 min. The milk was then heated to 165° F.and held at 165° F. for 5 min under agitation.

To 8.9 kg skim milk at 40-60° F., 83.5 g NFDM was added and the milk wasmixed for 10 minutes. Milk was heated to 120° F. and thecarrageenan/milk was added slowly and mixed for 5 minutes. Milk washeated to 149° F., held at that temperature for 5 min, then cooled to90° F. The calcium complex was added slowly, the milk was mixed for 10min, and 0.75 g cream/milk flavor was added. The pH was adjusted with10% potassium hydroxide solution to 6.9-7.0. The solids content waschecked.

The calcium fortified milk was placed in 330 ml glass jars, autoclavedfor 5 min at 250° F. then cooled to room temperature.

The autoclaved milk fortified with Ca-CITREM-citric acid complex at atotal calcium level of 2160 ppm performed similarly to the UHTsterilized samples--see Example 2, UHT sterilization (SI).

We claim:
 1. A separately formed calcium complex formed by theinteraction of a calcium source with a negatively charged emulsifier andwith an organic or inorganic acid selected from the group consisting ofcitric, lactic, malic, fumaric, gluconic, succinic, tartaric, ascorbic,or phosphoric or a salt thereof.
 2. A complex according to claim 1wherein the calcium source is calcium hydroxide, calciumcarbonate,calcium chloride, calcium phosphate, calcium sulfate, calciumnitrate, calcium lactate, calcium fumarate, calcium citrate, calciumacetate, calcium glycerophosphate or calcium oxide.
 3. A complexaccording to claim 1 wherein the negatively-charged emulsifier is acitric acid ester of monoglycerides, stearoyl lactylate (sodium,calcium, or acid), enzyme modified lecithin, stearyl citrate, fattyacids and their salts, or a diacetyl tartaric acid esters ofmonoglycerides.
 4. A complex according to claim 1 wherein the emulsifieris in a hydrated form.
 5. A complex according to claim 1 which is in adry form.
 6. A process of preparing a complex which comprisesinteracting a suitable calcium source with a negatively chargedemulsifier, optionally with an organic or inorganic acid or a saltthereof under interaction conditions sufficient to form the complex. 7.A process of preparing a complex according to claim 6 which comprisesadding acid or a salt of the acid to the emulsifier with mixing, andthen adding the calcium source.
 8. A process according to claim 6wherein, when an alkaline calcium source is added, the pH of the systembecomes neutralized.
 9. A process according to claim 6 wherein when anon-alkaline calcium source is added, this is followed by neutralizationwith an alkaline agent.
 10. A fortified foodstuff comprising a foodstuffand a fortifying amount of a complex comprising calcium and anegatively-charged emulsifier with or without an organic or inorganicacid or a salt thereof.
 11. A fortified foodstuff according to claim 10wherein the foodstuff is a dairy based product, a liquid nutritionalproduct, a beverage, or a confectionary product.
 12. A fortifiedfoodstuff according to claim 10 wherein the foodstuff is a milkbeverage, a juice or ice cream.
 13. A process of preparing a fortifiedfoodstuff as claimed in claim 10 which comprises forming a complex andthen adding the complex to the foodstuff.
 14. A process of preparing afortified foodstuff according to claim 13 wherein the complex is addedin an amount sufficient to provide from 5% to 200% of the recommendeddaily allowance for calcium in the foodstuff.
 15. A process according toclaim 13 wherein the foodstuff is a milk beverage or ice cream.
 16. Aprocess of preparing a fortified foodstuff according to claim 13 whereina stabiliser is added to the foodstuff.
 17. A process according to claim16 wherein the stabiliser is carrageenan, xanthan, gellan, pectin,alginates, gum arabic, carboxymethylcellulose, modified and unmodifiedstarches, propylene glycol alginate, locust bean gum, guar gum,hydroxylpropyl cellulose, hydroxypropylmethyl cellulose, methylcellulose or mixtures of two or more thereof.
 18. A fortified foodstuffaccording to claim 10 wherein the complex is present in an amountsufficient to provide from 5% to 200% of the recommended daily allowancefor calcium in the foodstuff.
 19. A fortified foodstuff according toclaim 10 wherein the foodstuff is a milk beverage or ice cream.